1. Field of the Invention
The present invention relates to a magnetic functional device mounted on a hard disk device, a magnetic sensor, or the like, and a magnetic head device comprising the magnetic functional device. Particularly, the present invention relates to a magnetic functional device capable of an increase in shape freedom of a support and an improvement of corrosion resistance, and a magnetic head device comprising the magnetic functional device. Also, the present invention relates to a magnetic head mounted on a hard disk device or the like to scan a recording surface of a disk in a CSS system, and a magnetic head device comprising the magnetic head. Particularly, the present invention relates to a side gap-type magnetic head capable of effectively realizing a decrease in the flying amount of the magnetic head, and decreasing damage to the disk and the magnetic head, and a magnetic head device comprising the magnetic head.
2. Description of the Related Art
FIG. 11 is a perspective view showing a magnetic head (magnetic functional device) M1 used for a conventional hard disk device, with a disk-facing surface turned upward.
As shown in FIG. 11, a magnetic element 1 comprising a magnetic reproducing element utilizing a magnetoresistive effect and an inductive thin film recording element is provided on the trailing-side end surface of a slider S1 which constitutes the magnetic head M1, a magnetic functional portion G of the magnetic element 1 being exposed at the slider surface. In the magnetic reproducing element, the magnetic functional portion G is a magnetic sensor element such as a spin valve thin film element, while in the thin film recording element, the magnetic functional portion G is a portion interposed between upper and lower core layers.
Also, a leading-side ABS 4 and a trailing-side ABS 5, which are subjected to a flying force (positive pressure) of an air flow between a disk and the slider S1, are formed on the slider surface of the slider S1 to protrude from a recording medium-facing surface 2.
Furthermore, a groove (air groove) 6 is provided on the recording medium-facing surface 2 to be surrounded by the leading-side ABS 4 and the trailing-side ABS 5, for providing negative pressure to the slider S1.
As shown in FIG. 15, a supporting member for supporting the magnetic head M1 comprises a load beam 11 having rigidity and exhibiting predetermined spring pressure at the base end, and a flexure 7 comprising a thin leaf spring provided at the tip thereof, the upper surface of the slider S1 being bonded to the flexure 7. The magnetic head M1 is movable in the pitch direction with the supporting end 7a of the flexure 7 as an oscillation fulcrum.
When the disk D is rotated, an air flow on the surface of the disk flows in between the disk D and the magnetic head M1 from the leading side. The air flow exerts positive pressure on the ABSs 4 and 5 in the direction to fly the magnetic head M1.
The magnetic head M1 flies in an inclined state in which the leading side thereof is raised from the disk, and scans the surface of the disk in a state in which the trailing side of the magnetic head M1 slightly flies above the disk D. In FIG. 15, the flying amount between the magnetic functional portion G of the magnetic head M1 and the disk D is X1.
FIG. 12 is an enlarged partial plan view showing only the periphery of the trailing-side ABS 5 shown in FIG. 11.
As shown in FIG. 12, the magnetic material layers of an upper core layer 8, an upper shield layer (upper core layer) 9 and a lower shield layer 10, which constitute the magnetic element 1, appear in the trailing-side ABS 5. Although not shown in FIG. 12, a magnetoresistive element such as a giant magnetoresistive element (GMR element) appears between the upper shield layer 9 and the lower shield layer 10. The magnetic functional portion G of the magnetic element 1 is determined by the distances between the upper core layer 8 and the upper shield layer 9, between the upper shield layer 9 and the magnetoresistive element, and between the lower shield layer 10 and the magnetoresistive element.
As shown in FIG. 12, the upper shield layer 9 and the lower shield layer 10 are formed to extend beyond the magnetic functional portion G in the width direction (the X direction shown in the drawing) of the slider S1. The width dimension of the lower core layer 9 and the lower shield layer 10 is T1.
Conventionally, in order to prevent both side ends of the lower core layer 9 and the lower shield layer 10, which are exposed at the trailing-side ABS 5, from protruding from the trailing-side ABS 5, the width dimension T2 of the trailing-side ABS 5 in the width direction of the slider S1 is set to be longer than the width dimension T1 of the lower core layer 9 and the lower shield layer 10.
However, the structure shown in FIG. 12 causes the following problem. The trailing-side corners A and B of the trailing-side ABS 5 readily collide with the disk D as the flying amount X1 (refer to FIG. 15) between the magnetic functional portion G and the disk D is further decreased with increases in the recording density in future. Particularly, when the magnetic head M1 is greatly inclined in the roll direction (refer to FIG. 11) during scanning on the disk D, the corners A and B more readily collide with the disk D.
In order to solve the above problem, as shown in FIG. 13, the width dimension of the trailing-side ABS 5 in the width direction of the slider S1 must be decreased from T2 to T3.
As a result, the corners A and B of the trailing-side ABS 5 are brought near the magnetic functional portion G, and thus collision of the corners A and B with the disk D can be appropriately prevented even when the flying amount between the magnetic functional portion G and the disk D is decreased with increases in the recording density.
Also, the surface area of the trailing-side ABS 5 is decreased, thereby decreasing adhesion torque during CSS driving.
However, in the trailing-side ABS 5 having the shape shown in FIG. 13, both side ends 9a and 10a of the lower core layer 9 and the lower shield layer 10, which are extended beyond the magnetic functional portion G in the width direction of the slider S1, protrude from the trailing-side ABS 5 to be exposed at the recording medium-facing surface 2.
FIG. 14 is a partial sectional view of the slider S1 taken along line XIV—XIV in FIG. 13, as viewed from the direction of an arrow.
As shown in FIG. 14, a protecting layer 12 is formed on the trailing-side ABS 5, but the protecting layer is not formed on the recording medium-facing surface 2. This is because the recording medium-facing surface 2 is formed by forming the protecting layer 12 over the entire surface of the slider S1, protecting the portions of the protecting layer 12, which correspond to the trailing-side ABS 5 and the leading-side ABS 4, with resist, removing the portion of the protecting layer 12, which is not covered with the resist, and then removing a portion of the slider surface exposed by removing the protecting layer 12.
Therefore, both side ends 9a and 10a of the lower core layer 9 and the lower shield layer 10 exposed at the recording medium-facing surface 2 are completely exposed to air, and further brought into contact with a solvent used in manufacturing the magnetic head M1, thereby causing the problem of corrosion of the lower core layer 9 and the lower shield layer 10. When the lower core layer 9 and the lower shield layer 10 are corroded, the recording properties and reproducing properties of the magnetic head 1 deteriorate, thereby failing to manufacture the magnetic head M1 appropriately adaptable to a higher recording density in future.
Also, the problem in which the portions of the magnetic element 1, which do not contribute to recording and reproducing, are exposed to deteriorate corrosion resistance is not limited to a magnetic head mounted on a hard disk device, and the problem occurs in other magnetic functional devices, for example, magnetic reproducing devices of a magnetic sensor, a magnetic tape, etc.
The shape of a support (a slider of a magnetic head) of a magnetic functional device greatly depends upon the shape of the magnetic element 1. Namely, for example, in a magnetic head, the shape of the trailing-side ABS 5 formed to protrude from the recording medium-facing surface 2 depends upon the shape of the magnetic element 1, in order to prevent excessive exposure of the lower shield layer 10 and the upper shield layer 9 at the recording medium-facing surface 2. Furthermore, when the shape of the trailing-side ABS 5 is determined, the other ABS 4 is also formed in a certain shape for securing flying stability in consideration of negative and positive pressures.
However, when the shape of the support depends upon the shape of the magnetic element 1 to decrease the design freedom of the shape of the support, there is a problem in which miniaturization of the support cannot be appropriately promoted.
FIG. 32 is a perspective view showing a magnetic head M1 used in a conventional hard disk device with the disk-facing surface turned upward.
As shown in FIG. 32, a magnetic element H comprising a magnetic reproducing element utilizing a magnetoresistive effect and an inductive thin film recording element is provided at the trailing-side end of a slider S1 which constitutes the magnetic head M1, a magnetic functional portion G of the magnetic element H appearing in the slider surface. In the magnetic reproducing element, the magnetic functional portion G is a magnetic sensor element such as a spin valve thin film element as a representative, while in the thin film recording element, the magnetic functional portion G is a portion interposed between upper and lower core layers (not shown in the drawing).
Also, a leading-side ABS 1 subjected to a flying force (positive pressure) of an air flow between a disk and the slider S1, rail surfaces 2 and 3 extending from both sides of the ABS 1 in the slider width direction to the trailing side, and trailing-side ABSs 8 and 10 are formed on the recording medium-facing surface 7 of the slider S1 to protrude from the recording medium-facing surface 7. The magnetic functional portion G appears in the trailing-side ABS 8. Furthermore, a groove (air groove) 4 is provided on the recording medium-facing surface 7 to be surrounded by the leading-side ABS 1, the rail surfaces 2 and 3, and the trailing-sides ABSs 8 and 10, for providing negative pressure to the slider S1.
As shown in FIG. 33, a supporting member for supporting the magnetic head M1 comprises a load beam 11 having rigidity and exhibiting predetermined spring pressure at the base end, and a flexure 6 comprising a thin leaf spring provided at the tip thereof, the upper surface of the slider S1 being bonded to the flexure 6. The magnetic head M1 is movable in the pitch direction with the supporting end 6a of the flexure 6 as an oscillation fulcrum.
When the disk D is rotated, an air flow on the surface of the disk flows between the disk D and the magnetic head M1 from the leading side through an inclined surface 1a. The air flow exerts positive pressure on the ABSs 1, 8 and 10 and the rail surfaces 2 and 3 in the direction to fly the magnetic head M1.
The magnetic head M1 flies in an inclined state in which the leading side thereof is raised from the disk, and scans the surface of the disk in a state in which the trailing side of the magnetic head M1 slightly flies above the disk D. In FIG. 33, the flying amount between the magnetic functional portion G of the magnetic head M1 and the disk D is X1.
The magnetic head M1 shown in FIG. 32 is a side gap-type magnetic head in which the magnetic functional portion G is formed at a position deviating from the center of the width dimension H1 of the trailing-side end of the slider S1 to one of the side ends of the slider S1 in the width direction (the X direction shown in the drawing).
In such a side gap-type magnetic head, in order to decrease the flying amount X1 between the magnetic functional portion G and the disk D, the trailing-side end is brought nearer the disk surface than the leading-side end, and the slider S1 is inclined in the roll direction relative to the disk D, as shown in FIG. 34 (a partial front view of the slider S1 shown in FIG. 33 as viewed from the direction of arrow B), thereby bringing the side end 1c of the slider S where the magnetic functional portion G is formed nearer the disk D than the other side end 1d. As a result, the magnetic functional portion G can be further brought near the disk D.
However, as shown in FIG. 35 (an enlarged partial plan view of FIG. 32), the magnetic functional portion G is conventionally formed at the center of the maximum width dimension T2 of the trailing-side ABS 8 where the magnetic functional portion G appears. Therefore, when the slider S1 is inclined in the roll direction as shown in FIG. 34, the corner A of the trailing-side end 8a of the trailing-side ABS 8 nearest the side end 1c of the slider S1 is brought nearest the disk D, not the magnetic functional portion G.
As shown in FIG. 34, the flying amount between the corner A and the disk D is X2 which is smaller than the flying amount X1 between the magnetic functional portion G and the disk D.
Therefore, when the flying amount X1 between the magnetic functional portion G and the disk D is excessively small, the corner A readily collides with the disk D, easily damaging the disk D and the magnetic head M1.
Therefore, the flying amount X1 between the magnetic functional portion G and the disk D must be increased by controlling the roll angle to avoid collision between the corner A and the disk D, thereby increasing a spacing loss and failing to manufacture the magnetic head M1 adaptable to a higher recording density.
Since control of the roll angle depends upon not only the flying amount X1 between the magnetic functional portion G and the disk D but also the flying amount X2 between the corner A and the disk D, the control is easily made troublesome.
Also, the above problem can be solved by decreasing the maximum width dimension T2 of the trailing-side ABS 8. However, with the excessively small width dimension T2, the surface area of the trailing-side ABS 8 is decreased to easily cause wearing of the ABS 8 with the disk D during CSS driving, and the positive pressure produced on the trailing-side ABS 8 is changed to undesirably cause the need to change the slider design. Therefore, the surface area of the trailing-side ABS 8 must be set to a predetermined value.